POS1408 AN ULTRASOUND NEGATIVE FOR SUBCLINICAL SYNOVITIS IN PATIENTS WITH ARTHRALGIA: IS IT HELPFUL IN IDENTIFYING THOSE WHO WILL NOT DEVELOP INFLAMMATORY ARTHRITIS? A LONGITUDINAL STUDY IN FOUR ARTHRALGIA COHORTS
Authors: C. Rogier, G. Frazzei, M. Kortekaas, M. Verstappen, S. Ohrndorf, E. Van Mulligen, R. Van Vollenhoven, D. Van Schaardenburg, P. De Jong, A. Van der Helm-van Mil
Journal: Annals of the Rheumatic Diseases (2022)

Background Ultrasound (US) has become an established method in the evaluation of joints and is often used in clinical practice to guide management decisions in arthralgia-patients. To date, studies on the prognostic value of MSUS in arthralgia focused on the positive predictive value of subclinical inflammation. However, also the absence of imaging-detected subclinical synovitis is now increasingly used in daily practice to exclude arthralgia-patients from further follow-up. Though, evidence on the value of a negative US in ruling out future IA development in arthralgia-patients (the negative predictive value) is mostly absent. According to the rules of Bayes, predictive values are highly dependent on the prior-risk of developing the disease. The NPV therefore, is strongly related to the prior-risk of not getting IA, which is quite considerable in arthralgia-patients. Objectives To investigate the negative predictive value (NPV) of musculoskeletal ultrasound (MSUS) in arthralgia patients at risk for developing inflammatory arthritis (IA). Methods An MSUS examination of hands and feet was performed in arthralgia-patients at risk for IA in four independent cohorts. Patients were followed for one-year on the development of IA. Subclinical synovitis was defined as greyscale≥2 and/or power Doppler≥1. NPVs were determined and compared with the prior risks of not developing IA. Outcomes were pooled using meta-analyses and meta-regression analyses. In sensitivity analyses, MSUS-imaging of tender joints only (rather than the full US-protocol) was analyzed and ACPA-stratification applied, the latter being in line with the use of US in daily care. Results After one-year 78%, 82%, 77% and 72% of patients in the four cohorts did not develop IA. The NPV of a negative US was 86%, 85%, 82% and 90%, respectively. The meta-analysis showed a pooled non-IA prevalence of 79%(95%CI: 75%-83%) and a pooled NPV of 86%(95%CI:81-89%) (Figure 1). Imaging tender joints only (as generally done in clinical practice) and ACPA-stratification showed similar results. Figure 1. Full US protocol; Prior risks of not developing IA (A) and negative predictive values of MSUS (B) in the four cohorts. For comparison, the pooled prior risk and confidence interval from A are depicted in the red column in B. Conclusion A negative US result in arthralgia has a high NPV for not developing IA, which is mainly due to the high a-priori risk of not developing IA. The added value of a negative US (&lt;10% increase) was limited. References N.A. Disclosure of Interests Cleo Rogier: None declared, Giulia Frazzei: None declared, Marion Kortekaas: None declared, Marloes Verstappen: None declared, Sarah Ohrndorf: None declared, Elise van Mulligen: None declared, Ronald van Vollenhoven Speakers bureau: Speaker, for which institutional and/or personal honoraria were received: AbbVie, Galapagos, GSK, Janssen, Pfizer, UCB, Consultant of: Consultancy, for which institutional and/or personal honoraria were received: AbbVie, AstraZeneca, Biogen, Biotest, BMS, Galapagos, Gilead, Janssen, Pfizer, Sanofi, Servier, UCB, Vielabio, Grant/research support from: Research Support (institutional grants): BMS, GSK, Lilly, UCB Support for Educational programs (institutional grants): Pfizer, Roche , Dirkjan van Schaardenburg: None declared, Pascal de Jong: None declared, Annette van der Helm-van Mil: None declared